Thermoset polyurethane matrix fiber reinforced composite

ABSTRACT

A composite fiber and resin reinforcement for strength members for use in the composite wood industry. The composite fiber and resin reinforcement is a fiber reinforced polymer (FRP) composite comprising a thermoset polyurethane resin matrix and a plurality of fibers. Typical uses will be as a reinforcing material for wood laminates, such as wood support beams (glulam), truck floors and truss fabrication.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims priority of U.S. Provisional Application No.61/188,325, filed Aug. 11, 2008, under Title 35, United States Code,Section 119(e), U.S. Provisional Application No. 61/188,290, filed Aug.8, 2008, under Title 35, United States Code, Section 119(e) and U.S.Provisional Application No. 61/188,473, filed Aug. 11, 2008, under Title35, United States Code, Section 119(e).

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to composite fiber and resinreinforcements for strength members. More particularly, the presentinvention relates to such composite reinforcements having improvedstrength over prior composite reinforcements. Even more particularly,the present invention relates to composite fiber and resinreinforcements to use in reinforced wood and wood based products such asreinforced structural laminated timber, reinforced structural lumber andreinforced glulam.

2. Description of the Prior Art

The concept of reinforcing products with fibers to strengthen theproducts in order to become structural members is known in the art. Theadvantage of doing so, the method for attachment, and conventionalmethods for making the structural members are also established in theart. For example, U.S. Pat. No. 5,928,735 (Padmanabhan, et al.), U.S.Pat. No. 6,179,942 (Padmanabhan, et al.), U.S. Pat. No. 5,456,781(Tingley) and U.S. Pat. No. 6,105,321 (KarisAllen) may be consideredrelevant in the art. It is known that the use of composites formed bythe pultrusion process is a convenient way to attain the use of fibersfor reinforcing products. This is further disclosed in U.S. Pat. No.6,037,049 (Tingley) and U.S. Pat. No. 5,362,545 (Tingley).

Pultrusion is generally defined as a continuous process of manufacturingof composite materials with constant cross-section whereby reinforcedfibers are pulled through a resin, possibly followed by a separatepreforming system, and into a heated die, where the resin undergoespolymerization and where the reinforced plastic is shaped and the resinis cured. Pultrusion is known for the ability to fabricate a continuouslength of reinforced plastic and to accommodate desired placement andorientation of fibers, which allows for the mechanical properties of thepultruded part to be designed for a specific purpose or application.Pultruded parts comprise longitudinally aligned fibers for axialstrength and obliquely aligned fibers for transverse strength. Manyresin types may be used in pultrusion, including polyester,polyurethane, vinylester and epoxy.

Reinforcements for structural members have been manufactured usingpultrusion processes. This process generally involves wetting fiberswith resin and pulling the wet fibers through a mold where the resin iscured by heating the resin. Exemplary pultrusion processes aredisclosed, for example, in U.S. Pat. No. 2,419,328 (Watson, et al.),U.S. Pat. No. 2,684,318 (Meek), U.S. Pat. No. 3,895,896 (White, et al.),U.S. Pat. No. 5,286,320 (McGrath, et al.), U.S. Pat. No. 5,374,385(Binse, et al.), U.S. Pat. No. 5,424,388 (Chen, et al.), U.S. Pat. No.5,556,496 (Sumerak), U.S. Pat. No. 5,741,384 (Pfeiffer, et al.) and U.S.Pat. No. 5,783,013 (Beckman, et al.).

Another type of pultrusion process, often referred to as continuouslamination, involves spreading resin on a film, such as MYLAR®, addingfiber materials to the spread resin and then adding a top cover film toform an envelope that essentially becomes a flexible mold. This“sandwich” configuration is shaped by tension and mechanical forces, andis then pulled through an oven to cure the “sandwich” configuration intoa desirable form.

A third variation of pultrusion provides placing the fibers undertension, saturating the fibers with photo-initiated resin, pulling thefibers through a series of sized dies or nip rolls to form the fibersinto a bundle or web, and then exposing the fibers to high intensityultraviolet light to initiate curing. A surface coating is then appliedand cured to provide a desired resin rich surface. This process has beenused in forming artificial leather and strengthening members of fiberoptic cables. Exemplary variations of this process are disclosed in U.S.Pat. No. 244,872 (Fischer), U.S. Pat. No. 4,861,621 (Kanzaki), U.S. Pat.No. 5,700,417 (Femyhough) and U.S. Pat. No. 6,893,524 (Green).

A fourth variation of pultrusion provides placing the fibers undertension, saturating the fibers with thermo-reactive resin, and pullingthe fibers through a series of sized dies to form the fibers into around bundle while they are exposed to elevated temperatures, such asthose found in an oven. This process has been used for making fishingrods, and has also been adapted for manufacturing fiberoptic cablestrength members.

Thermoset polyurethane resin has shown the ability to be formulated toadjust the flexibility, elasticity and tensile properties. Thiselasticity has provided a more secure bonding to man-made fibers, suchas aramid and nylon, as shown in U.S. Pat. No. 4,695,509 (Cordova, etal.). The adjustable formulations are highlighted in several patentsthat show the capabilities for making a very tough product, asexemplified in U.S. Pat. No. 6,787,626 (Dewanjee).

Some difficulties with the current art have been identified. Forexample, the pultrusion process as discussed above is limited. Theclosed die method becomes less efficient when the thickness of thefibers is at 0.030″ and less because of the lack of space for foreignobjects, crossed fibers, fiber knots and splices. This is complicatedwith the use of rigid resins like polyester, vinyl ester, epoxy, acrylicand others as the interlaminate shear is reduced and the product cansplit longitudinally (i.e., parallel to the fibers) quite easily whilein process, as well as during post processing. In this instance, theprocessing speed will also be kept to less than 10 ft. per minute.

A method for providing a greater interlaminate shear (to reduce thesplitting) in thicknesses below 0.030″ comprises adding a web ofmaterials to the structure. The web of materials has fibers indirections other than parallel to the longitudinal fibers. In doingthis, an amount of the longitudinal fibers must be replaced in anormally disproportional amount, thus reducing the product strength andrequiring a thicker laminate to enable the same reinforcing function.

Many of the open (i.e., without a die or cover envelope) processes havebeen substantially limited to the making of round products, and morespecifically to the making of products having a thickness below 0.035″and when substantially all of the fibers are longitudinal fibers. Inaddition, the more commonly used resins of polyester and vinyl esterrelease harmful emissions that increase when cured in an open processand are required by state and federal laws to be limited.

Existing patents and procedures for reinforcements bonded to wood do notinclude the use of thermoset polyurethane resin. Thermoset polyurethaneresin has a number of desirable characteristics including goodflexibility, elongation and resistance to corrosion. However, the use ofthermoset polyurethane resin for reinforcements has been thought to betoo flexible, too hard to use as a matrix in the reinforcement, and todisplay poor bonding to adhesives. It should be noted that there is adifference between thermoplastics and thermosets. Thermoplastics usuallycontain additives to change the properties of the material such aspolypropylene while thermosets usually contain catalysts that change thestate of the material at the molecular level. Thermoplastics can bere-melted and recycled fairly easily. Thermosets typically are cured andmolded into shape and are not recycled as easily. U.S. Pat. No.6,749,921 (Edwards et al.) specifically states that the use of athermoplastic polyurethane composite provides an avenue for the shapingof and hammering nails into the wood composite, which are not possibleusing fiber-reinforced thermoset composites due to their brittleness.Therefore, Edwards et al. teaches away from the use of a thermosetpolyurethane composite in the wood composite industry.

There is thus a need for an improved composite fiber and resinreinforcement for strength members for use in reinforced wood and woodbased products having good flexibility, elongation and resistance tocorrosion.

SUMMARY OF THE PRESENT INVENTION

The present invention involves an improved composite fiber and resinreinforcement for strength members. The present invention relates toimproved composite reinforcements having improved strength and athickness of 0.035″ and under, and in particular, 0.030″ and under.

The composite fiber and resin reinforcements for strength memberscomprises a thermoset resin matrix and is reinforced with predominantlycontinuous fibers. The inventive reinforcements can be incorporated as aintegral reinforcing material to combine with or attach to otherproducts for providing an increased strength to those other products,such as wood support beams (glulam), wood laminates, truck floors andtrusses. If used as a integral reinforcement material, the inventivereinforcements can be manufactured as an ingredient of other productssuch as wood or wood-based products. If manufactured as a separatematerial, the inventive reinforcements may be physically secured toother products by adhesion or the like. The reinforcing material canalso be used to strengthen composite thermoplastic lumber, otherthermoplastic extrusions and moldings, and aluminum extruded products.The reinforcement material can also be added to pultruded or moldedthermoset plastic products to allow for specific areas of increasedstrength while maintaining a low reinforcement level in other areas. Thereinforcement material can also allow for a resin rich surface whichcreates a smooth surface that is more resistant to chemicals andultraviolet light, and acts as a shield, for other pultruded or moldedthermoset plastic products.

According to one broad aspect of the present invention, there isprovided a composite fiber and resin reinforcement that includes amatrix material comprising a thermosetting polyurethane resin, andfibers provided within the resin matrix, where the resin matrix has anelongation similar to that of the reinforcing fibers so the load on theentire reinforcement is more evenly distributed.

It is an object of the present invention to provide a reinforcingmaterial for wood or wood-based products that includes a thermosettingpolyurethane resin and reinforcing fibers provided within the thermosetpolyurethane resin. The reinforcing fibers comprise fiber tows orientedsubstantially parallel to each other. The thermosetting polyurethaneresin has an elongation-to-failure value that is substantially equal toor greater than an elongation-to-failure value of the reinforcingfibers.

Still another object of the present invention is to provide a reinforcedbeam with a reduced width as compared to a standard width beam, whilebeing able to bear an equivalent load.

Another object of the present invention is to provide a composite fiberand resin reinforcement which is produced at a lower weight, materialcost and capital cost as compared to conventional composite componentsusing traditional resin systems.

Other objects will become apparent from the description to follow andfrom the appended claims.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic illustration of an apparatus according to thepresent invention for manufacturing a composite strength member.

FIG. 2 is a schematic illustration of an alternative tensioningmechanism in accordance with an embodiment the present invention.

FIG. 3 shows in schematic form another alternative tensioning mechanismin accordance with the present invention according to one of itsembodiments.

FIG. 4 is another schematic illustration of an alternative tensioningmechanism in accordance with one embodiment of the present invention.

FIG. 5 is yet another schematic illustration of an alternativetensioning mechanism in accordance with an embodiment of the presentinvention.

FIG. 6 is a schematic rendition of internal chambers of an impregnatoraccording to an embodiment of the present invention.

FIG. 7 shows in schematic form a hole size and hole placement in animpregnator entrance plate according to an embodiment of the presentinvention.

FIG. 8 is a conceptual schematic illustration of an alternativeimpregnator showing the internal profile to reduce areas of non-flowingresin according to an embodiment of the present invention.

FIG. 9 is a conceptual schematic illustration of an alternativeimpregnator showing its internal profile for slow processing accordingto the present invention according to an embodiment.

FIG. 10 illustrates in conceptual form an alternative impregnatorshowing the internal profile thereof for slow processing where resin potlife is not a factor according to another embodiment of the presentinvention.

FIG. 11 is a conceptual schematic illustration of the forming andinitial curing area according to an embodiment of the present invention.

FIG. 12 is a conceptual schematic illustration of an optional liquidcoating and curing station according to an embodiment of the presentinvention.

FIG. 13 is a schematic representation of an apparatus for manufacturinga composite strength member while attaching to a receiving memberaccording to an embodiment of the present invention.

FIG. 14 is cross-sectional perspective view of a composite strengthmember resulting from the method in accordance with the presentinvention pursuant to one of its embodiments.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The present invention is now described with reference to the drawings,wherein like reference numerals are used to refer to like elementsthroughout. In the following description, for purposes of explanation,numerous specific details are set forth in order to provide a thoroughunderstanding of the present invention. It will be evident, however, toone skilled in the art that the present invention may be practicedwithout these specific details.

According to an exemplary embodiment, a method and apparatus areprovided for producing a composite fiber and resin reinforcement forstrength members to use in preparing reinforced wood and wood-basedproducts. The composite fiber and resin reinforcement are provided inthe form of a thermoset polyurethane matrix for use in the production oftruck flooring, reinforced wood beams and the like.

The improved resin system is intended to provide the compositecomponents with relatively high bending and compressive strength suchthat the components may be produced without the need to provide fiberreinforcement in the transverse direction (i.e., the directiontransverse to the longitudinal or “pulling” direction). Such componentsmay advantageously be produced at a lower weight, material cost, andcapital cost as compared to the production of conventional compositecomponents using traditional resin systems. In contrast to conventionalpultrusion processes that utilize transverse fibers (e.g., webs or matsof fibers incorporated in the component), the production speed of thecomposite components according to the exemplary embodiments describedherein are not slowed by the addition of the transverse fibers, therebyrequiring fewer machines to supply the desired quantity in a given timeframe.

Fibers may be rovings, tows, strands, yarns, other fiber bundles or evenindividual filaments. The terms “rovings”, “tows” and “strands” arenomenclature that are used in the fiber industry. Fiberglass fibers arereferred to as roving while carbon fibers are known as tows. Aramidfibers may be referred to as rovings, tows and strands. Strands can alsorefer to the filaments that make up the roving or tows. A broad range offiber materials may be used with the thermoset polyurethane resinmatrix. For example, fibers may be made of materials selected fromfiberglass, basalt, aramid, carbon, nylon, polyester, polyethylene,ceramic, boron, steel, metal alloys, and other natural and man-madefibers. Specifically, it has been found that basalt, fiberglass andaramid fibers are preferred due to sufficient strength and relativelylow cost. Carbon fibers are preferable if very high tensile strength isnecessary and if electrical conductivity is allowable. Aramid fibersresist any potential creep in the fiberglass fibers. Fiberglass andbasalt are the lowest cost fibers. Basalt fibers can replace fiberglassfibers. Basalt is stronger than some fiberglass but is also higher inprice. Basalt is more chemical resistant than fiberglass and would notdegrade as quickly if exposed to water and other environmentalcontaminants. Both fiberglass and basalt are also the heaviest fibers.Therefore, if reduced weight becomes more important than cost,fiberglass and basalt may be replaced by carbon fibers or aramid.

The thermoset polyurethane resin precursor system includes anisocyanate, a polyol or polyol blend, and a system of lubricants andother additives that are typically referred to as a “mold release.” Theisocyanate is also referred to as MDI (methylene diphenyl diisocyanate).Mold release is a commercial internal release agent which allows theresin to release from the die as it cures to a solid form. Threemanufactures of mold release include Axel, Tecklub and Stevens. Theresin system may also optionally include one or more polymeric additivesthat may be used to modify the surface of the resulting component, tomodify the physical properties of the component, to provide improvedprocessing, or to provide other benefits. Additionally, the resin systemmay include one or more fillers which may act passively to reduce thecost of the overall resin system (e.g., by taking the place of morecostly constituents) or may actively fimction to provide improvedphysical properties or improved processing.

Pigments may be optionally added to the resin system to create a desiredcolor for the composite. The pigments can be commercially purchased froma company such as Plasticolors, Inc. of Ashtabula, Ohio. Wetting agentsmay be used to increase the effective wetting of the resin to thefillers and the fibers as detailed below. Wetting agents are availablefrom sources such as BYK-Chemie GmbH of Germany. Zinc sterate lubricantmay be optionally used as a mold release to penetrate between the resinand the die surface, but also serves as a lubricant between the fibersand the filler particles to make the resin mix act like it is “slippery”so that less processing problems arise. During a normal pultrusionprocess, there is a possibility that the resin may stick to the dieduring curing, and a mold release serves the function to prevent this.The zinc sterate is attracted to the steel die surface and remainsthere, creating a barrier between the resin and the die. Therefore, whenresin cures, the resin is not cured into the pores of the steel. Whenthe resin acts “slippery,” the fibers slide or “flow” to areas of lesspressure to provide a more even fiber content rather than piling up inone area. If fibers are all bunched in one area, they may require moreforce to move through the die, and this force could cause fiber failure.Peroxide catalysts are available from a catalyst supplier and may beused to initiate the single part thermoset polyurethane resin by causingcross linking between the resin molecules and styrene or other monomermolecules in the resin. The commercial resin suppliers such as PlexinateLtd. of New Zealand and Reichhold Inc. of N.C., recommend a peroxide toinitiate their one part resin systems.

The amount of fibers in the thermoset polyurethane resin matrix dependson the desired thickness of the reinforcement. For example, areinforcement for a truck floor is typically 0.028-0.032 inches thick,and should contain between 50%-70% fiber by volume. A more preferablerange is 60%-65% fiber by volume.

A thermoset polyurethane resin matrix has an elongation similar to thatof the reinforcing fibers so the load on the entire reinforcement isevenly distributed. The elongation of basalt is 3.15%. The elongation offiberglass is 3.5% and the elongation of aramid is 2.9%. The thermosetpolyurethane resin elongation can be adjustable with the common industrystandard additives, fillers and resin specifics since these additives donot elongate with the resin. Therefore, more additives and less resinequates to less elongation. Some of these additives, fillers and resinspecifics include mineral fillers such as calcium carbonate, clay,glass, and others are rigid chunks, spheres, or flakes that reduce theeffective elongation of the completed and cured resin mixture, becausethese additives replace the resin and do not themselves elongate asstated above. The available polyols as well as the availablecommercially prepared resins will have different elongations dependingon their individual proprietary formulas. For example, some companieslike Plexinate offer a proprietary flexiblizer to increase theelongation of their one-part polyurethane. The industry also offers athermoplastic polyvinyl acetate (PVA) that may be added tonon-polyurethane resin mixes such as vinyl ester and polyester toprovide some increase in elongation. A thermoset polyurethane resinmatrix elongation value in excess of the fiber elongation value isneeded to prevent fracture of the resin. Having a higher fiberelongation value than the resin matrix elongation value causes weaknessin the reinforcing material because the fibers are not supported by theresin matrix after the resin matrix is destroyed from being elongatedpast its limits.

In its final form, the reinforcing material comprises a first pair ofgenerally opposed sides parallel to each other and a second pair ofgenerally opposed sides parallel to each other, where the two sets ofsides enclose an internal section comprising the thermoset polyurethaneresin matrix and the reinforcing fibers. The first set of sides has awidth greater than the width of the second set of sides, i.e. the shapeof a rectangle. The shape of the reinforcing material usually matchesthe shape of the wood or wood-based product. However, other shapes, bothregular and irregular could be utilized. The thickness of thereinforcing material is usually less than 0.060 inches. Preferably, thereinforcing material is less than 0.035 inches which creates anelongated flat-like structure or sheet-like structure. The flat-likestructure has a length and width that is at least 13 times greater thanthe thickness of the reinforcing material. This elongated flat-likestructure may be in the form of a web, a plate or a plank. It is alsopossible that the reinforcing material could have other profilecharacteristics such as ribs or other irregularities.

The thermoset polyurethane resin system has a toughness that will allowfor impacts, abrasion, and flexing that would damage other systems. Thetoughness and the elongational properties of the thermoset polyurethaneresin matrix reduce the tendency for cross-fiber splitting (i.e.splitting between the fibers) and after-assembly damage potential.Cross-fiber splitting occurs when a fracture develops between the fiberswhich may result during handling of a reinforcement and in the procedureto attach a reinforcement to the wood or wood-based products when aforce is applied at other than parallel to the fibers. It should benoted that after the reinforcement is attached to the wood or wood-basedproduct, forces other than parallel to the fibers would not result incross-fiber splitting because the reinforcement is “sandwiched” betweenthe wood and such forces could not gain access to the reinforcementbetween the wood. For example, the reinforcement may be attached to a2×4 piece of wood, with the reinforcement lying flat on top of the 2×4and bonded to the 2×4 by an adhesive. A second 2×4 may then be placed ontop of the reinforcement and may also be attached via an adhesive. Theonly exposed part of the reinforcing material would be the thickness ofthe material, which is usually under 0.060 inches. Therefore, thereinforcing material is “sandwiched” in between the two pieces of wood.After-assembly damage may occur when fasteners such as nails or otheritems are forced through a reinforcement when attached to the wood orwood-based product and further separate the fibers. After-assemblydamage may also include underlying wood damage resulting from the woodreceiving an impact that causes a crack or splintering of the wood orfrom rotted wood. However, the elongation properties of the resin matrixof the present invention significantly reduce any cross-fiber splittingand after-assembly damage that could occur. The resin matrix allows thereinforcement to be ductile rather than brittle. Therefore, anymishandling of the reinforcement would not result in a fracture thatwould lead to cross-fiber splitting. Regarding after assembly damage, ifa nail is forced through the reinforcement, the resin matrix willelongate or stretch rather than fracture under the impact. Therefore,the fibers will remain intact with the resin matrix and will not splitor be separated. In addition, the bonding of the resin to the fibersreduces the tendency of internal cracks that are more common in otherresin systems which can propagate and lead to cross-fiber splitting.

The thermoset polyurethane resin mix can be prepared using commerciallyavailable polyurethane 2-part resin systems. Some suppliers of thepolyurethane 2-part resin systems include Bayer MaterialScience LLC ofPittsburgh, Pa., Huntsman Advanced Materials of France, BSAF—TheChemical Company of Germany and Resin Systems Inc. (RSI) of Canada.Additional fillers and colors may be added to the polyol side asdesired. Commercially available polyurethane 1-part resin systems canalso be used to create the thermoset polyurethane resin mix. Suppliersof 1-part resin systems include Plexinate, Reichhold and Ashland. The1-part resin systems may be supplemented with additional ingredients asnormal in the industry for polyester resin systems. In the alternativeto a commercially available polyurethane resin, polyols and isocyanatein the chemical or commodity markets may be separately purchased andthen combined to form the thermoset polyurethane resin.

Optionally, a nylon veil may be added to the FRP composite forincreasing cross-wide strength during manual handling of the FRPcomposite and to further reduce any potential for cross-fiber splitting.The nylon veil is added to keep the FRP composite flat so good surfacecontact is achieved with the wood or wood-based product. The nylon veilmay be placed on one or both sides of the FRP composite. The nylon veilmay be 0.010 inches thick. It has been found that a suitable nylon veilis produced by Cerex Advanced Fabrics, Inc. under the trademark Cerex®.

Strength testing has shown that a standard beam width beam may bereduced in width when the reinforcement of the present invention isused. For example, it has been found that a typical 5⅛ inch wood membercan be reduced in size to a 3⅛ inch wooden member when the reinforcementof the present invention. This is a substantial amount of reduction woodthat leads to lower costs and materials.

The following specific examples may be used to construct various truckfloor reinforcements to be used with wood. The 3.5 inch wide materialreinforcement was arbitrarily chosen based on customer specifications.Other beam widths may also used depending on customer specification.

EXAMPLE 1

According to an exemplary embodiment, a 3.5 inch wide truck floorreinforcement was prepared using 34 tows of 3420 aramid, 96 strands offiberglass roving 900 yield, 12 strands of fiberglass roving 250 yield,a 3.6 inch wide and 0.010 inch thick nylon veil (Cerex®), and a 2-partpolyurethane resin with 15% filler. The numeral “3420” when describingthe aramid fibers is the nomenclature used by Teijin Aramid (amanufacturer of aramid fibers) and refers to the unit of measure(decitex) of the fiber which is a determination of weight per length.“Tex” is a unit of measure for the linear mass density of fibers and isdefined as the mass in grams per 1000 meters. The decitex, abbreviated“dtex”, is the mass in grams per 10,000 meters. The fiberglass roving900 yield is a nomenclature used in the U.S. to determine the weight perlength. A 900 yield means that the size is sufficient to provide 900yards in a pound. Cerex® is the brand name, as noted above, of the nylonveil material that is made from continuous nylon strands heat bondedtogether to form a fine mesh.

EXAMPLE 2

According to another exemplary embodiment, a 12.43 inch wide truck floorreinforcement was prepared using 110 tows of 3420 aramid, 506 strands offiberglass roving 900 yield, and a 1-part polyurethane resin.

EXAMPLE 3

According to yet another exemplary embodiment, a 12.43 inch wide truckfloor reinforcement was prepared using 20 tows of 3420 aramid, 605strands of fiberglass roving 900 yield, a 12.5 inch wide 0.010 inchCerex®, and a 1-part polyurethane resin.

EXAMPLE 4

According to still another exemplary embodiment, a 12.43 inch wide truckfloor reinforcement was prepared using 630 strands of basalt roving 900yield, 12.5 inch wide 0.010 inch Cerex®, and a 1-part or 2-partpolyurethane resin.

The following specific examples may be used to construct variousreinforcing materials to strengthen wood or wood-based beams.

EXAMPLE 5

According to an exemplary embodiment, a 3.5 inch wide beam reinforcementwas prepared using 40 tows of 3420 aramid, 98 strands of fiberglassroving 900 yield, 20 strands of fiberglass roving 250 yield, and a1-part or 2-part polyurethane resin with 18% filler.

EXAMPLE 6

According to another exemplary embodiment, a 3.5 inch wide beamreinforcement was prepared using 40 tows of 3420 aramid, 72 strands offiberglass roving 900 yield, 20 strands of fiberglass roving 250 yield,and a 1-part or 2-part polyurethane resin with 5-25% filler.

The following are some typical polyurethane resin mix formulations thatwere used or can be used in the above examples:

Materials amount Dow Polyol 1000 Mold release 63 Filler 560 BayerIsocyanate (MDI) 1600 Pigment 65 RSI part A resin 500 RSI part B MDI 500Bayer part A resin 500 Bayer part B MDI 500 Filler 180 Mold release 25Pigment 25 Wetting agent 1 Reichhold Extreme resin 1000 Filler 300Pigment 33 Mold release 7 Zinc sterate lubricant 15 Byk w996 Wettingagent 3 Peroxide catalyst 20 Plexinate resin 900 Plexinate flexablizer100 Filler 300 Pigment 33 Mold release 7 Zinc sterate lubricant 15 Bykw996 Wetting agent 3 Peroxide catalyst 20

The reinforcing material of the present invention can be produced byknown pultrusion methods as discussed in the Description of the PriorArt above. However, various processing problems arise when producing areinforcing material less than 0.060 inches in thickness. Due to theminimal thickness of the reinforcing material, it is common for fibersto cross over or form knots in the matrix because the limited space inthe resin matrix. As discussed above, cross over fibers can lead toexcessive fiber percent by volume which can lead to fracture of thefibers. Therefore, the following method is preferable to produce areinforcing material composite under 0.060 inches thick and morepreferably about 0.030 inches thick.

Referring to FIG. 1, a schematic representation of an apparatus for oneembodiment for the method in accordance with the present invention isshown and referred to generally at numeral 1. Creels 10, 11 are providedfrom which various desirable fibers 12, 13 are supplied to apparatus 1.A broad range of fiber materials may be used in accordance with thepresent invention. For example, fibers 12, 13 may be rovings, tows,yarns, other fiber bundles or even individual filaments. In particular,fibers 12, 13 may comprise materials selected from fiberglass, basalt,aramid, carbon, nylon, polyester, polyethylene, ceramic, boron, steel,metal alloys, and other natural and man-made fibers as known in the artand are unidirectional reinforcing fibers (i.e., having a 0-degreeorientation) wherein part or all of the reinforcing fibers comprise theman-made or natural fibers. Alternatively, at least some of theplurality of fibers may be obliquely aligned fibers (i.e., having otherthan a 0-degree orientation) for further improving the transversestrength. In particular, the reinforcing fibers are comprised entirelyor at least partially of carbon fibers, aramid, fiberglass, and basalt.In accordance with the present invention, the plurality of fibers may berandom, woven, sewn or swirled reinforcing fibers. Still further, theplurality of fibers is held in tension by the resin matrix. In theembodiment shown in FIG. 1, fibers 11 comprise aramid and fibers 12comprise fiberglass.

A tensioning device (not shown in FIG. 1) is provided for tensioningeach of fibers 12, 13 that are supplied to the process. The tensioningdevice may be provided on creels 10, 11 at the point of exit of fibers12, 13 from creels 10, 11. However, it should be appreciated that thetensioning device may be provided at any advantageous point between theexit point of fibers 12, 13 to the entrance of the impregnator(discussed below). For example, the specific positioning of thetensioning device may depend on the specific fibers employed and whichare exiting creels 10, 11. In this embodiment, the tensioning device 20is associated with creels 10, 11. In other words, the tensioning deviceis attached to creels 10, 11 which contain fibers 12, 13 so that fibers12, 13 are under tension when entering an impregnator or an impregnationchamber 22 (discussed further below). The tensioning devices may becommercial units, which are conventional in the art or even custom madeunits and may be inline, i.e., integral to the process in accordancewith the present invention. However, it should be appreciated that theemployment of the tensioning device is not required as normal travel offibers 12, 13 through the process of the present invention will providesufficient tension onto fibers 12, 13 to facilitate completion of theend product. Nevertheless, the use of the tensioning device may beadvantageous to pre-stress the fibers for producing a stronger endproduct.

The tensioning device comprises brake wheels (not shown) for providingthe tension. The brake wheels resist the unwinding of the various fibers12, 13 from creels 10, 11. In other words, the brake wheels prevent thefibers from unraveling and may also be a variation of a tensioningdevice. In accordance with the present invention, the tensioning devicecreates a substantially equal amount of tension in each of thelongitudinal fibers 12, 13 of the finished reinforcement.

Referring now to FIGS. 2-5, various alternative embodiments of atensioning device are shown and described in schematic form for use withthe method of the present invention, and referred to generally atnumeral 20. The alternative tensioning devices 20 enable the tensioningof the fibers 12, 13 to be manually and/or electronically controlled foradjusting the specific tension on fibers 12, 13. With reference to FIG.2, fibers 12, 13 pass through a pair of non-aligned ceramic eyelets 48.A bearing roller 160 and weight ball 162 provide tension onto fibers 12,13 as fibers 12, 13 are pulled through eyelets 48. Bearing roller 160may comprise ultra high molecular weight polyethylene (UHMWPE), ceramicor any other comparable wear-resistant and non-abrasive material knownin the art. Weight ball 162 should be of a size and weight so as not toprovide excessive tension onto fibers 12, 13. In particular, the tensionplaced on the fiber that is produced by the weight ball assembly may bein the range between 0.2-10 lbs, and more particularly in the rangebetween 1.5-3 lbs (i.e., pound-force).

Referring to FIG. 3, a biasing spring 152 is employed for pushingagainst pressure disks 150 to provide a compressive force on fibers 12,13 as fibers 12, 13 pass between pressure disks 150. It should beappreciated that pressure disks 150 are conventional in the art and maybe commercial units comprising conventional steel disks.

Referring to FIG. 4, a rubber belt 252 and a brake controlled sheave 250compresses the fibers 12, 13 to create tension in the fibers 12, 13 asfibers 12, 13 pass through pair of eyelets 48.

Referring to FIG. 5, a pair of ceramic eyelets 48 is provided on amovable member 350 which may be advantageously rotatable or pivotable.In this embodiment, pair of ceramic eyelets 48 aremoveable/pivotable/rotatable to various angles to adjust the amount oftension in the fibers 12, 13 as fibers 12, 13 pass through pair ofeyelets 48. For example, ceramic eyelets 48 are pivotable not more than135° and in particular are pivotable not more than 90° relative to thex-axis.

Referring back to FIG. 1, fibers 12, 13 which are under tension arepassed through an optional fiber pre-treating or pre-heating station 19.Pre-treating or pre-heating station 19 is advantageous for heatingfibers 12, 13 prior to entry into an impregnator 22. Fiber pre-treating,such as by pre-treating in a fiber pre-treating chamber or fiberpre-heating station 19 may be an oven, a heater or a comparable highertemperature chamber to warm the surface of fibers 12, 13 in order toremove material from the surface of fibers 12, 13 and to drive offmoisture in fibers 12, 13 or from the surface of fibers 12, 13. Forexample, fiber pre-treating/pre-heating station 19 may bring the surfacetemperature of fibers 12, 13 to be up to about 120° F. for fibers otherthan aramid. In the instance where pre-heating of aramid is required,the surface temperature of the aramid fibers 12, 13 may be up to about350° F. Fiber pre-treating/pre-heating station 19 may be anelectrostatic or plasma chamber when a plasma or corona treatment isrequired for modifying the surface of fibers 12, 13. Plasma or coronatreatment is an electric discharge field through which the fibers traveland which modifies the surface of the fibers. Plasma or corona treatmentis advantageous for facilitating the bonding of the resin matrix to thefibers for increasing the particular desired properties of the finishedproduct.

The treated fibers 12, 13 subsequently pass into an impregnator 22 andare saturated with resin 24. The resin 24 for saturating fibers 12, 13may be curable by conventional cure treatments. Cure treatments whichmay be employed in the present invention, include thermal contact,thermal radiation, photo-radiation, electron beam radiation, and radiofrequency (e.g., microwave) radiation. In one embodiment, the resin 24is a thermosetting resin that is capable of being cured by thermalcontact and/or thermo-radiation. In particular, the resin may be anyresin that can be converted from a liquid stage by molecularcross-linking initiated by heat or other energy, (e.g., a thermosetresin). Examples of such resin 24 include polyesters, vinyl esters,epoxy, phenolic and mixtures of polyesters, vinyl esters, epoxy,phenolic or polyurethane. In particular, the resins in accordance withthe present invention may include entirely or at least in part thermosetpolyurethane resin, thermoset phenolic resin, thermoset polyester resin,thermoset epoxy resin, thermoset melamine resin, and thermoset acrylicresin, or combinations thereof. The ratio of the plurality of fibers tothe resin matrix in accordance with the present invention is about from20% to about 60% by volume, more particularly about from 30% to about50% by volume, and even more particularly about from 40% to about 50% %by volume.

As shown in FIG. 1, a supply system or pump 21 supplies resin 24 toimpregnator 22. A supply system may be a meter system, a mixing systemor a catalyzation system. System or pump 21 is an apparatus that istypically commercially available and known in the art for delivering aspecified ratio of components to facilitate the ultimate complete curefor the resin 24. The components are then passed through a commerciallyavailable static mixer (not shown) and fed into the impregnator 22 as ahomogenous mixture. The static mixer may be any conventional staticmixer known in the art and is positioned at the end of the tubing of thepump system where the components come together in the impregnator 22.The pump system 21 allows for custom blending and catalyzation toprovide for faster reacting resin 24 with less concern for reduced potlife because the quantity that is catalyzed is comparably small.

The wet or saturated fibers 12, 13 are then subjected to forming withinthe impregnator 22. Forming fibers 12, 13 within the impregnator 22facilitates appropriately locating the various fibers 12, 13 relative toeach other. In this embodiment, a package of longitudinally aligned andtensioned fibers 12, 13 are created. Fibers 12, 13 are located adjacenteach other with liquid resin 24 generally filling the space between thefibers 12, 13 when they exit the impregnator 22.

Referring to FIG. 6, impregnator 22 will be discussed in greater detail.Impregnator 22 comprises five chambers to fully wet and saturate andposition the fibers 12, 13 relative to each other and with the resin 24.Impregnator 22 comprises an entrance plate 50, which comprises a platehaving through-holes 50 a through which fibers 12, 13 pass for entryinto a flooding chamber 51. Through-holes or bushings 50 a are of asufficient diameter and length to prevent leakage of resin 24 passingtherethrough or to prevent resin 24 from flowing back out of theimpregnator 22, e.g., a diameter of at least ⅛ inch and a length in therange of 1 inch-3 inches and more particularly in the range of1.25″-1.5″. The length and diameter of the holes or bushings 50 a mayalso depend on the particular pressure and the viscosity of the resin24, as well as the speed of the fibers 12, 13 passing therethrough.Determination of optimum speed would be determined by one skilled in theart. For example, through-holes or bushings 50 a having a diameter of ⅛inch and a length of 1 inch may be compatible with through speeds of atleast two feet/minute. The entrance plate 50 or the bushings 50 acomprise a wear resistant material, such as hardened steel, stainlesssteel or ceramic.

Flooding chamber 51 is a space provided adjacent to entrance plate 50for allowing the resin to free flow around the entering fibers 12, 13.Flooding chamber 51 may be an area of under one inch in lengthimmediately following the entrance plate 50 with only slightcross-section area reduction over that length. An increase in thislength will not hinder the present invention, except that a greateramount of resin will remain in process that would be subject topremature curing in the impregnator 22. The actual decrease incross-section of flooding chamber 51 determines the transition betweenflooding chamber 51 and compaction chamber 52 (discussed below). Forexample, reduction in the area of the flooding chamber 51 of more than10% reduction determines the transition between flooding chamber 51 andcompaction chamber 52.

As indicated above, a compaction chamber 52 is the chamber immediatelyfollowing flooding chamber 51. Compaction chamber 52 is a progressivelynarrowing chamber for allowing fibers 12, 13 to be brought closertogether for initiating some contact between fibers 12, 13, forgenerating the initial removal of voids from between fibers 12, 13 andfor filling those voids with resin 24. The cross-sectional area ofcompaction chamber 52 is reduced to about 10% to 30% over its length,and more particularly to about 15% to 25%. The length of compactionchamber 52 may be about 1.5 times the height measured at the transitionof the flooding chamber 51 and the compaction chamber 52. An increase inthis length will not hinder the present invention, except that a greateramount of resin will remain in process that would be subject topremature curing in the impregnator 22.

A substantially wedge-shaped pressure chamber 53 immediately followscompaction chamber 52. Saturation of fibers 12, 13 is completed atpressure chamber 53 and fibers 12, 13 are subjected to their maximumpressures (e.g., 50 psi) and moved into the desired shape. The shallowand progressive incline of the wedge shape of pressure chamber 53provides for the pressure increase. As the fibers 12, 13 are pulledthrough pressure chamber 53, fibers 12, 13 pull resin 24 that is incontact with or in proximity to fibers 12, 13. As pressure chamber 53gets smaller or narrower, less resin 24 will fit so excess resin 24 ispushed back towards the entrance of pressure chamber 53. The resistanceto flow of resin 24 and the attachment and attraction of resin 24 tofibers 12, 13 cause an increasing pressure along the length of pressurechamber 53. This pressure forces resin 24 into any remaining voids infibers 12, 13. The amount of taper over the length of pressure chamber53 is somewhat dependant on the particular materials chosen and thethroughput speed involved, but generally a decrease in cross-sectionalarea may be 5% to 15%, or advantageously 8% to 10%, of the originalcross-sectional area as measured at the transition between compactionchamber 52 and pressure chamber 53 to accomplish sufficient saturationand shaping of fibers 12, 13.

Still referring to FIG. 6, an exit mouth 54 is provided as the finalarea of impregnator 22. As the law of fluid dynamics indicates, thepressure loss occurs over a length of a tube and if the length is tooshort the fluid will simply increase in speed to allow more volume topass. Exit mouth 54 incorporates this law of fluid dynamics to provideenough length to contain the resin pressure in the pressure chamber 53and to limit the amount of excess resin 24 that overflows fibers 12, 13.Exit mouth 54 is an opening with substantially parallel sides from whichfibers 12, 13 and resin 24 exit impregnator 22, and the fibers have arelatively narrow cross-sectional diameter. The length of exit mouth 54may be between 0.5″ and 4″, and more particularly may be between 1″ and2″. The running speed of the impregnation chamber of impregnator 22 maybe about 2 inches/minute to about 10 feet/minute. The cross-sectionaldiameter of exit mouth 54 may be about the same as pressure chamber 53at the transition between pressure chamber 53 and exit mouth 54.

Returning to FIG. 1, after passing through impregnator 22, fibers 12, 13may have various tendencies to cause fibers 12, 13 to spring away fromeach other. This phenomenon is caused by the individual strandspring-like rigidity of fibers 12, 13, the liquid viscosity of the resinbeing too low to hold the fibers 12, 13 in place and the ratio of fibers12, 13 to resin 24 being relatively high. In accordance with the presentinvention, the ratio of fibers 12, 13 to resin 24 is about from 10% toabout 70% by volume, with results in the range of about 20% to about 60%by volume, with better results in the range of about from 30% to about50% by volume, and with the best results in the range of about from 40%to about 50%. In order to avoid the surface from becoming too irregularfrom the aforementioned tendency and to maintain a compact and resinrich surface, the saturated fibers 12, 13 and resin 24 are passedbetween a heated die bottom 27 and an upper support pressure pad 28 foreffecting the initial cure and for at least partially curing andpartially solidifying the resin 24.

Upper support pressure pad (or top pressure pad) may be, in accordancewith the present invention, a flexible top die 28. Flexible top die 28advantageously accommodates any sections or portions of high thicknessof saturated fibers 12, 13 passing between heated die bottom 27 and topdie 28 and facilitates the passing therebetween without disrupting theprocess. Flexible top die 28 may advantageously comprise a materialwhich is flexible enough to accommodate a spot thickness change of 50%of the reinforcement thickness. The flexibility of the top die 28 shouldcome from a thin, hard substance as wear from the contact with themoving reinforcement is present and release from the forming surface isnecessary. The flexible top surface may advantageously comprise aflexible silicone rubber belt that runs with the reinforcement andrelease (i.e., peel free) because of its elasticity. A flexible steelbelt could also be employed. Still further, for example, a steel shimstock may be employed as the material for flexible top die 28. Thethickness range of flexible top die 28 may advantageously be about from0.010″ to 0.030′ and should comprise enough strength and wear resistanceto be compatible in accordance with the present invention. Flexible topdie 28 may further optionally include a backup of springs, air pillow orbladder (discussed further in relation to FIG. 11 below) to hold top die28 in order to maintain an average thickness requirement. Alternatively,a hot oil bladder may be employed for both effectively heating the topdie 28 and also for providing the required flexibility and pressure ontosaturated fibers 12, 13 passing therebetween. The bladder could evenfurther be a stainless braid and silicone (or other high temperaturesynthetic rubber) hydraulic and oil heater hose, or even comprisesections of such hose running across the travel direction of the fibers.In the case where a flexible steel belt is employed as top die 28, anadditional external mold release may be applied to the surface of thebelt when it is not in contact with the curing reinforcement.

The combination of heated die bottom 27 and upper support pad 28comprise an initial curing station. It should be appreciated by oneskilled in the art that the resin should not stick to the die (i.e.,heated die bottom 27 and upper support pad 28) during the presentprocess. A mold release agent may be employed for providing alubricating barrier between the resin and the surrounding die. Forexample, a zinc sterate lubricant may be used as a mold release topenetrate between the resin and the die surface. It should beappreciated that zinc sterate is attracted to the steel die surface andsits there, so when the resin cures, the resin does not cure or getstuck into the pores of the steel because the zinc sterate creates abarrier between the steel die and the resin. The zinc sterate alsoserves as a lubricant between the fibers and the filler particles sothat the resin mix obtains for reducing any potential processingproblems arise. Any alternative lubricant which is conventional in theart could of course also be employed.

Referring to FIG. 7, a schematic depiction of entrance plate 50 is shownhaving a plurality of holes 50 a. Entrance plate 50 forms a typical holeplacement and diameter for up to three fiberglass rovings of a 900 yieldor 3 aramid fibers of a 3200 denier placed in each hole. Any number ofholes 50 a may be employed as desired or necessary.

Referring now to FIG. 8, a schematic depiction of the internal profileof an alternative impregnator is shown at numeral 22 a. Alternativeimpregnator 22 a comprises a configuration to limit dead spaces whereresin 24 can remain stagnate and cure prematurely. The configuration ofimpregnator 22 a facilitates the flow of resin 24 and the paths offibers 12, 13 in order to continually displace old resin 24 with freshresin 24. A purge section 23 is also provided in the alternativeimpregnator 22 a. Purge section 23 may be adjusted or raised to open theexit area of the impregnator for removal of obstructions or for anyother relevant reasons. Purge section 23 provides for a moveable orremovable section to be incorporated into impregnator 22 a to allow forpartial disassembly to purge a process problem, such as broken orbunched-up fibers, without having to undesirably disassemble the entireimpregnator 22 a.

Referring now to FIG. 9, another alternative embodiment of impregnator22 is shown and referenced to at numeral 22 b. Impregnator 22 b in thisembodiment may be employed for use with long pot life resin. In thisembodiment, impregnator 22 b demonstrates modified internal profiles andpurge section 23 dimensions that can be used with slower throughputspeeds of under 15 feet/minute, or even under 10 feet/minute.

Referring now to FIG. 10, yet another alternative embodiment ofimpregnator 22 is shown and referred to at numeral 22 c. In thisembodiment, impregnator 22 c demonstrates modified internal profilesconcepts and dimensions that can be used with slower throughput speedsof under 15 feet/minute where the pot life of the resin is of longertime.

Referring now to FIG. 11, the primary forming and curing area inaccordance with the present invention is shown. Fibers 12, 13 are shownentering impregnator 22 through the entrance plate 50 and the resin 24is shown entering the impregnator 22 through static mixer 23. Thesaturated fibers 12, 13 are then shown continuing on between die bottom27 and top pressure pad 28 and subsequently exiting as a compositeproduct 40. A pressure bladder 28 a may also be provided on top of toppressure pad 28 to equalize the pressure in the system.

Referring again to FIG. 1, after passing through the initial curingstation 27 and top pressure pad 28, the composite product 40 may passbetween a pair of optional embossing rolls or rollers 30 to transfersurface irregularity or texture to the surface of the composite product40. Rollers 30 may comprise any material conventional in the art.

The process of the present invention can further include the applicationof a veil (not shown) around the cured composite 40 for stabilizing thecured composite 40 and for improving cross-wide strength. It should beappreciated that application of the veil would be understood to oneskilled in the art. Veil may be applied after the exit from impregnator22 and prior to post-curing. It should also be known to one skilled inthe art that veil may comprise nylon, but may also comprise any materialconventional in the art which is thin, strong and has a high heattolerance, such as fiberglass, aramid, carbon, sand, and the like.Materials such as carbon-based materials and metals may be employed forproviding improved conductivity.

The heat generated by the initial curing station 27 and top pressure pad28 may be sufficient in this embodiment of the present invention toprovide the necessary amount of heat required to complete curing. Itshould be appreciated by one skilled in the art that the particularamount of heat generated by the initial curing station is directlydependent on the particular speed and the particular length of the diewhich are employed. However, in instances where reduced cure is desiredfor embossing the surface or if higher line speed is desired, moreforced curing may be desired. Alternatively, a post cure chamber 36 maybe employed to provide additional heat sources. Exemplary heat sourcesmay be, but are not limited to, infrared heaters, radio frequency (e.g.,microwave) heaters, or other conventional devices to provide thermalradiation, convection or high intensity light for photo-initiation.

Referring to FIG. 12, an optional coating station is shown and referredto at numeral 32. Optional coating station 32 can be included in theprocess of the present invention after composite product 40 passesthrough post curing chamber 36 to provide an additional coating to thecomposite products on the surface of the strength member. The additionalcoating may be applied and cured by any known method which isconventional in the industry. Optional coating station 32 comprises acoating reservoir 81 that will wet the surface of a coating wheel 82,which in turn transfers the coating to be applied to the compositestrength member 40 as it passes across coating wheel 82. A scraper, suchas a doctor blade 83, removes any excess coating and reduces dripping.An air knife 84 (or any comparable device known in the art) completesthe even spreading of the coating onto composite strength member 40. Forexample, a photo-initiated coating may be employed, whereby ultra violetlamps 85 are in turn employed to activate the coating in order tocomplete the curing of the coating.

Returning to FIG. 1, pairs of wheels 38 are provided to operate aspuller clamps to pull the cured composite 40 out of post cure chamber36, if post cure chamber 36 is employed. In this embodiment as shown inFIG. 1, two pairs of wheels (i.e., four total wheels) are provided.However, additional or fewer pairs of wheels may be provided asnecessary. Alternative puller clamps may include caterpillar treads oranother clamp and pull source as known in the art. In this embodiment, adrive mechanism (not shown) drives pairs of wheels 38. Pairs of wheels38 provide the force which works in combination with the tensioningdevice 20 to cause tension on fibers 12, 13 throughout the curingprocess. Thus, fibers 12, 13 in accordance with the present inventionare under a constant longitudinal tension while resin 24 is cured.Puller clamps 38 feed the cured composite 40 to a roll-up station 40 forstoring and subsequent processing. Alternatively, the cured strengthmember may be delivered to a cutting station (not shown), whereby thereinforcements are cut into desired sizes and shapes.

Referring now to FIG. 13, an alternative embodiment of the process ofthe present invention is shown and described. The method as shown inFIG. 13 is an alternative mode of incorporating the method for makingthe strength member into an attachment to a first receiving member 141.One section of the initial curing station is replaced with a preparedreceiving member 141 that will travel with the process. Heated diebottom 27 (in FIG. 1) is replaced with a bottom support pad or rollers129 and the top pressure pad 128 is heated. The fibers 112, 113 andresin 124 exit the impregnator/impregnation chamber 122 and are laidonto a first receiving member 141 where the heated top pressure pad 128will affect the adhering to and curing to of the composite 140 to thereceiving member 141. From the exit of the initial curing station, theprocess will continue as shown and described in FIG. 1, with theoptional step of adding a second receiving member 143 for making a“sandwich” configuration of the strength member. In this embodiment,first receiving member 141 and second receiving member 143 may be of thesame material or may different.

The alternative embodiment of the process for manufacturing a continuousfiber reinforced thermoset plastic material comprises the steps oftensioning the fibers, guiding the fibers through a pre-treatingstation, saturating the fibers with resin in an impregnator, positioningthe impregnated fibers onto first receiving member 141 and initiatingcure at a curing station, applying an optional surfacing embossing andreceiving any surface coating, adding second receiving 143 member ontothe composite, applying pressure to form a sandwich configuration,guiding the sandwich configuration through a post-cure station anddirecting the sandwich configuration through a pulling mechanism foraccumulation and storage for future use in lengths as desired. Theprocess for manufacturing a continuously formed fiber reinforcedcomposite strength member in proximity to receiving members, wherein thestrength member is fabricated of fiber-reinforced composite materialcomprising a plurality of fibers impregnated with a polymeric matrix,results in a composite wherein the plurality of fibers are substantiallyunidirectional reinforcing fibers, and the plurality of fibers that areimpregnated with a polymeric matrix are substantially aligned along thelongitudinal dimension of the strength member.

As shown in FIG. 13, a tensioning device (not shown) is optionallyprovided for placing fibers 112, 113 in tension. Fibers 112, 113 passthrough an optional pre-treating station 119. Pre-treating station 119is selected from the group consisting an oven, infrared heater, or anelectrostatic plasma device. Fibers 112, 113 are then saturated in animpregnator 112 having the same configuration as that described in FIGS.1 and 6, namely, comprising, an entrance plate with holes for the fibersto pass through of sufficient length and cross-sectional area to limitthe resin leaking from inside the impregnator and to position the fibersfor effective coating and desired final alignment inside theimpregnator, a flooding chamber to allow the resin that is fed into theimpregnator to flow around and come into contact with the fibers, acompaction chamber to move the fibers closer together and to initiatethe resin wet-out of the fibers having an exit cross-sectional area thatis reduced to about 15% to 25% of its entrance cross sectional area anda length that is about 1.5 times the entrance height, a pressure chamberto complete the resin saturation and fiber alignment having an exitcross-sectional area that is reduced to about 8% to 10% of its entrancecross-sectional area and a length that is about 30 times the entranceheight, and an exit mouth to maintain the fiber placement and to reducethe amount of excess resin which exits the impregnator having sides thatare substantially parallel and a length of about 1″ to 2″.

Receiving members 141, 143 are selected from the group consisting ofaluminum, steel, metal alloys, thermoplastic, thermoset plastic, woodand wood products, and combinations of man made and/or naturalmaterials, and receiving member 141, 143 may be the same as each otheror may be different. As shown in FIG. 13, plurality of fibers 112, 113are impregnated with a polymeric matrix inside impregnator 122 and areplaced onto first receiving member 141 and are directed into an initialcuring station 127. Initial curing station 127 comprises curing selectedfrom the group consisting of thermal contact, thermal convection,infrared, ultraviolet, electron beam and radio frequency, and thepolymeric matrix is at least partially cured. The partially curedcomposite strength member is then directed into an optional embossingroll 142 for implanting a surface texture onto the exposed sides of thecomposite 140. The partially cured composite strength member is thendirected onto an optional coating station (not shown in FIG. 13) forplacing a coating onto the exposed side of the composite. The coatingmay be at least partially cured and may be selected from the groupconsisting of adhesives, paints, primers, surface treatment, activationchemicals, bonding agents, and other protecting or preparing materials.Second receiving member 143 joins composite strength member 140 andfirst receiving member 141, and is positioned to form a sandwichconfiguration with the strength member being in the center position withreceiving members 141, 143 on either side. Opposing pressure is appliedon the receiving members 141, 143 so that the strength member iscompressed between the receiving members 141, 143.

Composite strength member 140 is then directed into a post cure chamber136. Post cure chamber comprises at least one method of curinginitiation selected from the group consisting of thermal contact,thermal convection, infrared, ultraviolet, electron beam, and radiofrequency, wherein the polymeric matrix is at least partially cured tothe degree that final cure either has occurred or may occur at a futurestate of use.

Referring to FIG. 14, a cross-sectional and perspective view of thestrength member 140 as produced in accordance with the present inventionis shown and described.

It is important to note that the composite component and resin systemdescribed in the various exemplary embodiments is illustrative only.Although only a few embodiments of the present inventions have beendescribed in detail in this disclosure, those skilled in the art whoreview this disclosure will readily appreciate that many modificationsare possible without materially departing from the novel teachings andadvantages of the subject matter recited in the claims. Accordingly, allsuch modifications are intended to be included within the scope of thepresent invention as defined in the appended claims. The order orsequence of any process or method steps may be varied or re-sequencedaccording to alternative embodiments. Other substitutions,modifications, changes and omissions may be made in the design,operating conditions and arrangement of the exemplary embodimentswithout departing from the scope of the present inventions as expressedin the appended claims.

1. A reinforcing material for wood or wood-based products for increasingthe useful strength of wood or for reducing the thickness, grade orweight of the wood or wood-based products without reducing the loadbearing value of comparable conventional wood or wood-based products,said reinforcing material comprising: a fiber-reinforced compositematerial comprising a plurality of fibers impregnated with a resinmatrix, wherein the plurality of fibers are predominantly unidirectionalreinforcing fibers aligned along the longitudinal dimension of thereinforcing material and said resin matrix comprises a thermosetpolyurethane resin.
 2. A reinforcing material according to claim 1further comprising: a first pair of generally opposed sides parallel toeach other and a second pair of generally opposed sides parallel to eachother, said two sets of sides enclosing an internal section comprisingsaid thermoset polyurethane resin matrix and said plurality ofreinforcing fibers, said first set of sides having a width greater thanthe width of said second set of sides, said first set of side and saidsecond set of sides forming an elongated flat-like structure.
 3. Areinforcing material according to claim 1 wherein said matrix furthercomprises at least one resin selected from the group consisting ofthermoset phenolic resin, thermoset polyester resin, thermoset epoxyresin, thermoset vinyl ester resin, thermoset resorcinol, thermosetmelamine resin and thermoset acrylic resin.
 4. A reinforcing materialaccording to claim 1, wherein at least a part of said plurality offibers are selected from the group consisting of aramid fibers,polyethylene, nylon, polyester, ceramic, fiberglass, carbon and basalt.5. A reinforcing material according to claim 1, wherein a ratio of saidplurality of fibers to the polymeric matrix is from about 40% to about50% by volume.
 6. A reinforcing material according to claim 1 having anoverall thickness of no greater than 0.035 inches.
 7. A reinforcingmaterial according to claim 1 having an overall thickness of no greaterthan 0.060 inches.
 8. A reinforcing material according to claim 1,further comprising a veil for increasing cross-wide strength duringhandling of said reinforcing material, said veil comprising a pluralityof random, woven, sewn or swirled reinforcing fibers.
 9. A reinforcingmaterial according to claim 8 wherein said veil comprises nylon.polyester, or other thermoplastic materials.
 10. A reinforcing materialaccording to claim 8 wherein said veil has a thickness of between 0.010inches and 0.050 inches.
 11. A reinforcing material according to claim 1wherein said thermoset polyurethane resin matrix further comprises a oneor two-part polyurethane resin.
 12. A reinforcing material according toclaim 1 wherein said thermoset polyurethane resin matrix furthercomprises between 5% and 25% filler.
 13. A reinforcing materialaccording to claim 1 wherein said elongated flat-like structure isselected from the group consisting of a web, a plate and a plank.
 14. Areinforcing material according to claim 1, wherein a ratio of saidplurality of fibers to the polymeric matrix is from about 50% to about70% by volume.
 15. A wood composite comprising; at least one woodenmember having two surfaces disposed in substantially parallel relationto one another; and at least one reinforcing material disposed at apredetermined location adjacent said at least one wooden member, saidreinforcing material comprising: a first pair of generally opposed sidesparallel to each other and a second pair of generally opposed sidesparallel to each other, said two sets of sides enclosing an internalsection comprising a thermoset polyurethane resin matrix and a pluralityof reinforcing fibers, said first set of sides having a width greaterthan the width of said second set of sides, said first set of sides andsaid second set of sides forming an elongated flat-like structure.
 16. Awood composite according to claim 15 wherein said elongated flat-likestructure is selected from the group consisting of a web, a plate and aplank.